Electric component including custom metal grain orientation

ABSTRACT

An electrical device includes an electromagnetic component configured to generate a magnetic flux. The electromagnetic component includes a soft magnetically-conductive material configured to pass magnetic flux therethrough along a flux path. The soft magnetically-conductive material includes at least one grain oriented portion having metal grains that are oriented parallel with respect to the magnetic flux.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/254,364, filed Nov. 12, 2015, which is incorporated herein byreference in its entirety.

STATEMENT OF FEDERAL SUPPORT

This invention was made with government support under DE-AR0000308awarded by the U.S. Department of Energy. The government has certainrights in the invention.

TECHNICAL FIELD

Various non-limiting embodiments are generally related to electriccomponents, and more particularly, to electromagnetic metal graincomponents.

BACKGROUND

Electromagnetic devices and machines such as electrical motors,transformers, etc., typically include a soft magnetically-conductivematerial to promote magnetic flux that is generated during operation ofthe device. Various types of soft magnetically-conductive material suchas electric steel, for example, can be fabricated to include metalgrains. In terms of electrical motors, for example, the flux generatedduring operation has a varying angle of incidence with respect to themetal grains formed in the soft magnetically-conductive material (e.g.,the stator).

Referring to FIG. 1A, for example, a distribution of flux generatedduring operation of a permanent magnet (PM) motor 100 at a first time(T1) is illustrated. The PM motor 100 includes a stator 102 and a rotor104. The stator 102 includes an outer ring 106 with twelve slots 108(e.g., forty-eight slots 108 would be shown in a full view). The rotor104 includes an inner ring 110 with poles 112. Each pole 112 is formedfrom a pair of rectangular magnets 114 (e.g., eight poles 112 would beshown in a full view). Turning to FIG. 1B, the flux distributiongenerated by the PM motor 100 at a subsequent time (T2) is illustrated.The flux paths 101 illustrated in FIGS. 1A-1B indicate the orientation(indicated by arrows 103) of the flux.

As shown in FIG. 1B, it is difficult to match the rolling (i.e.,rotational) direction of the soft magnetically-conductive material,e.g., steel, 1 with the flux (i.e., flux paths 101) at a particularmoment in time. Therefore, the soft magnetically-conductive material ofthe stator 102 and/or rotor 104 included in conventional motors 100 istypically fabricated having non-grain orientated metal 116 a-116 b. Thatis, the rotor metal grains 116 a and the stator metal grains 116 bformed in the soft magnetically-conductive material of conventionalmotors 100 have an orientation that is irrespective of the flux paths101. As a result, the metal grains 116 a-116 b (i.e., the grains andtheir boundaries) that are not aligned (i.e., are not parallel) with theflux paths 101 at a particular moment in time act as flux obstacles thatreduce efficiency and performance of the electromagnetic device becausethe non-alignment generates more reluctance for the flux to flow therebycontributing to increase losses.

SUMMARY

According to a non-limiting embodiment, an electrical device includes anelectromagnetic component configured to generate a magnetic flux. Theelectromagnetic component includes a soft magnetically-conductivematerial configured to pass magnetic flux therethrough along a fluxpath. The soft magnetically-conductive material includes at least onegrain oriented portion having metal grains that are oriented parallelwith respect to the magnetic flux.

According to another non-limiting embodiment, a method of fabricating anelectric device comprises determining flux paths of a softmagnetically-conductive material of the electric device, and determiningexpected amplitudes of the flux paths and comparing the expectedamplitudes to an amplitude threshold. The method further comprisesselectively forming grain oriented metal portions in the softmagnetically-conductive material. The method further includes formingthe grain oriented metal portions at low amplitude locations where theexpected flux amplitude is at or below the amplitude threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the present disclosure isparticularly pointed out and distinctly claimed in the claims at theconclusion of the specification. The foregoing and other features, andadvantages of the present disclosure are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1A is a sectional view of a motor showing a flux distribution at afirst time;

FIG. 1B is a sectional view of a motor showing the flux distribution ata second time;

FIG. 2 illustrates an electrical device including an electric componenthaving a custom metal grain orientation according to a non-limitingembodiment;

FIG. 3 illustrates the electrical device of FIG. 2 showing various metalgrain zones of the stator;

FIG. 4A illustrates a half cross-section of an electrical transformerdevice including grain oriented soft magnetically-conductive sheets; and

FIG. 4B illustrates an electrical transformer device including a cutawayportion showing a custom metal grain orientation according to anothernon-limiting embodiment.

DETAILED DESCRIPTION

Various non-limiting embodiments provide an electromagnetic device thatincludes a soft magnetically-conductive material having a controlledmetal grain orientation. The grain-orientation of the softmagnetically-conductive material is controlled such that metal grainsare oriented at strategic locations so as to match the direction of theflux path. In this manner, the performance and efficiency of theelectromagnetic device is optimized. In at least one embodiment, thegrain orientation grain orientation refers to the morphology/shapeand/or the crystallography of the grain.

Various embodiments employ additive manufacturing techniques combinedwith additional post-processing processes to fabricate softmagnetically-conductive material components such as electric steelstators, rotors, and transformer straps, for example, with control overthe morphology of the grains and/or crystallographic texture on thelevel of an individual laminate. At least one embodiment includes arotating machine having a rotor that rotates with respect to astationary electric steel stator. The electric steel stator isfabricated with a controlled grain orientation. In at least oneembodiment, the grain orientation refers to the morphology/shape and/orthe crystallography of the grain. The controlled metal grains extendradially along the teeth as well as circumferentially on the outer edge,sometimes referred to as a back iron or yoke, where the flux path isnearly constant. At transition regions where the flux direction ischanging, non-grain oriented electric steel may be employed. Thus, atleast one embodiment includes one or more zones or locations withspecifically oriented metal grains.

In at least one embodiment, the laminate can be also manufactured withradially grain oriented teeth and a non-grain oriented transitionsection for better cost effectiveness. As previously mentioned,achieving this differentiation may be accomplished through additivetechniques and post processing. The specific additive methods to betargeted include processes that employ an energy source, either laser orelectron beam, to selectively melt the steel alloy powder. The processparameters of the additive system such as the tool speed, energy sourcepower, powder flow rate, etc. can be adjusted to control grain size,shape and location. As for crystallographic texture, this can bedeveloped through either seeding off of a substrate with the desiredcrystal texture or by post build thermo-mechanical methodologies. Thislatter concept essentially supports the rolling and heat treatmentapproach used to control grain orientation at one or more strategiclocations. For instance, the morphology/shape of the grain and/or thecrystallography of the grain can be controlled at one or more strategiclocations of the soft magnetically-conductive material.

In at least one embodiment, the electrical component is fabricated as atransformer including grain oriented metal portions formed in one ormore corner regions. The linear path of flux may be achieved bysub-sectioning the core to enforce the desired flux path. In thismanner, regions of the straps falling outside the grain-oriented metalzone may be removed from the transformer, thereby reducing overallweight and improving efficiency.

Turning now to FIG. 2, an electrical device 150 including an electriccomponent having a custom metal grain orientation is illustratedaccording to a non-limiting embodiment. Unlike conventional electricdevices that provide non-grain oriented metal components, the custommetal grain orientation provided by at least one embodiment of theinvention matches the distribution of flux so as to improve theperformance and efficiency of the electrical device. As illustrated inFIG. 2, the electrical device 150 according to at least one non-limitingembodiment includes a permanent magnet (PM) motor 200. It should beappreciated, however, that the electrical device 150 may include othertypes of motors including, but not limited to, induction motors, switchreluctance motors, etc., or other types of electromagnetic devices suchas, for example, transformers.

The PM motor 200 includes a stator 202 and a rotor 204. The stator 202includes an outer ring 206 with twelve slots 208 (e.g., forty-eightslots 208 would be shown in a full view). The slots 208 define aplurality of stator teeth 209 extending radially between an innercircumference of the stator 202 located adjacent the rotor 204 and anopposing outer circumference of the stator 202. The rotor 204 includesan inner ring 210 with poles 212. Each pole 212 is formed from a pair ofrectangular magnets 214 (e.g., eight poles 212 would be shown in a fullview). The stator 202 and/or the rotor 204 are formed from a softmagnetically-conductive material. In at least one embodiment, the softmagnetically-conductive material is electric steel comprising acombination of iron (Fe) and silicon (Si). In at least one embodiment,the steel may comprise about 6.5 weight percentage (wt. %) of silicon.During operation the, PM motor rotor 200 generates flux. The fluxorientation 216 changes as the rotor rotates and create flux thattravels along various flux paths 218.

Unlike conventional PM motors which include a rotor and/or statorcompletely formed of non-grain oriented metal (see FIGS. 1A-1B), the PMmotor 200 according to least one non-limiting embodiment includes astator 202 and/or rotor 204 having customized grain oriented metalformed at one or more strategic locations. In this manner, fluxthroughput is increased so as to improve the overall performance of thePM motor 200.

In at least one embodiment, the stator 202 includes one or more grainoriented metal portions 220 a-220 b and one or more non-grain orientedportions 222. The grain oriented metal portions 220 a-220 b arestrategically formed at locations respective to the orientation 216 ofthe flux paths 218. Control over the morphology of the grains andcrystallographic texture on the level of an individual laminate may beachieved using various rolling and heat treatment techniques thatdevelop elongated grains along the rolling direction as well ascrystallographic texture aligned with the rolling direction.

For example, strategic locations of grain oriented and non-grainoriented portions may be controlled using additive techniques and postprocessing. Various additive methods to be targeted include processesthat employ an energy source, either laser or electron beam, toselectively melt the steel alloy powder. Various process parameters ofthe additive system such as the tool speed, energy source power, powderflow rate, etc. can be adjusted to control grain size and morphology orshape. Crystallographic texture can also be controlled through eitherseeding off of a substrate with the desired crystal texture or by postbuild thermo-mechanical methodologies. This latter concept essentiallysupports the rolling and heat treatment approach according to the grainorientation, i.e. a grain orientation process.

According to a non-limiting embodiment, a first grain oriented metalportion 220 a is formed along the radial direction of one or more of thestator teeth 209. In this area, the flux paths 218 extend radially andsubstantially parallel to the radial direction of a respective statortooth 209. Accordingly, the metal grains are formed having a radialorientation that matches the radial direction of the flux paths 218corresponding to the respective stator tooth 209. That is, the grain ofthe first metal grain portion 220 a is parallel or substantiallyparallel to the radial direction of the respective stator tooth 209, andthus the radial direction of the corresponding flux path 218.

As further illustrated in the non-limiting embodiment of FIG. 2, asecond grain orientated metal portion 220 b is formed along the outercircumference of the stator 202, sometimes referred to as the outersection of the stator yoke. In this area of the stator 202, the fluxpaths 218 are predominately circumferential, and at times may travelperpendicularly with respect to the flux paths 218 in the stator teeth209. In areas where a significant deviation from the circumferentialorientation occurs, the amplitude of the flux is relatively small. Forinstance, a flux threshold can be determined and amplitudes falling ator below the flux threshold may be identified as relatively smallamplitudes.

These relatively small amplitudes include amplitudes of flux (much)below the magnetic saturation level specific to the particularsoft-magnetic material. At magnetic saturation level in the areas withsignificant deviation losses can be prohibitive to use oriented steel.Therefore, the orientation of the metal grain formed at the second grainoriented metal portion 220 b is formed parallel with the direction ofthe flux flowing through the outer section of the stator yoke. That is,the metal grain of the second grain orientated metal portion 220 b isformed substantially circumferential so as to match the circumferentialorientation of the flux paths 218 at the outer circumference of thestator 202.

In some areas of the stator 202, however, the flux paths 218 havevarious directional paths or vectors. For instance, the flux paths 218existing where the stator teeth 209 meet the outer circumference orstator yoke have various non-consistent orientations. Some flux paths218 may travel in a radial direction while other flux paths 218 maytravel in a circumferential direction. As a result, the amplitude of theflux is relatively high compared to the flux amplitudes at the statorteeth 209 and/or exterior circumference. For instance, amplitudesexceeding the flux threshold may be considered a relatively highamplitude. These relatively high amplitudes include amplitudes thatexist at or above the magnetic saturation level specific forsoft-magnetic material. Accordingly, the non-grain oriented portions 222can be formed at these high-flux areas as further illustrated in FIG. 2.

In at least one embodiment, the rotor 204 may also include one or moregrain oriented metal portions 220 c. As illustrated in FIG. 2, the fluxpaths 218 located between the poles 212 and the inner circumference ofthe rotor 204 are substantially aligned with the radial paths dictatedby the stator teeth 209. Accordingly, a third oriented metal portion 220c may be formed between the poles 212 and the inner circumference of therotor 204, where the grains are orientated in substantially radialorientation, or an orientation that is substantially parallel with theflux paths 218 corresponding to the magnets 214 of a respective pole212.

Although specific locations of grain oriented metal portions 220 a-220 cand non-grain oriented metal portions 222 are described above, theinvention is not limited thereto. Referring to FIG. 3, for example, thestator 202 may be sectioned into one or more metal grain zones 224 a-224c. Each metal grain zone 224 a-224 c may be formed entirely of aparticular grain orientation or non-grain orientation. For instance, afirst metal grain zone 224 a including a majority portion of the statorteeth 209 may be formed having a radial metal orientation that matchesthe radial direction of the flux paths 218 flowing through the statorteeth 209. A second metal grain zone 224 b including a minor portion ofthe stator teeth 209 and a minor portion of the outer statorcircumference may be formed having a non-grain metal orientation sincethe flux paths 218 in this area vary and are inconsistent. A third metalgrain zone 224 c including the majority of the outer statorcircumference may be formed having a circumferential metal orientationthat matches the circumferential direction of the flux paths 218 flowingthrough the outer circumference of the stator 202.

Turning to FIG. 4A, an electrical device 300 including an electriccomponent having a metal grain orientation is illustrated. Theelectrical device 300 includes a transformer with core built from grainoriented laminations. The ability to control the grain orientation inthe transformer 300 improves performance relative to one containing onlynon-oriented grains.

Still referring to FIG. 4A, a half section of the transformer 300 isshown. The transformer 300 includes a plurality of vertical straps 302 aand a plurality of horizontal straps 302 b. The vertical straps 302 aextend along a vertical axis (e.g., Y-axis) to define a vertical length.The horizontal strap 302 b extends along a horizontal axis (e.g.,X-axis) to define a horizontal length. The horizontal strap 302 b caninclude a single strap with a center portion cut out to accommodate thecenter vertical strap, or can include two individual straps such thateach end of the vertical straps 302 a is coupled to the horizontal strap302 b. The points at which the center vertical straps 302 a are coupledto the horizontal strap 302 b define a beveled edge 304. The bevelededges 304 between adjacent straps (e.g., an end of vertical strap 302 aand an end of the horizontal strap 302 b) prevent field concentration atthe corners. In this manner, losses at the corners of the transformer300 are reduced. In at least one embodiment, the transformer 300includes a center vertical strap 302 a interposed between a pair ofouter vertical straps 302 a. In this case, the transformer 300 includesa horizontal strap 302 b with a cutout in the center that is coupled tothe center vertical strap 302 a.

Flux paths 306 a-306 b are shown travelling in directions correspondingto the lengths of the straps 302 a-302 b. For instance, vertical fluxpaths 306 a extend vertically along the length (i.e., Y-axis) of thevertical straps 302 a. Horizontal flux paths 306 b extend horizontallyalong the length (i.e., X-axis) of the horizontal strap 302 b.

Unlike conventional transformers, at least one embodiment provides atransformer 300 including a custom grain orientation formed in thearched corner zone 308. The frame of the transformer 300 may havevarious cross-sectional shapes including but not limited to,rectangular-shaped frame. The custom grain orientation includes archedmetal grains 310 as illustrated by the cutaway portion shown in FIG. 4B.In this manner, a direct connection between the vertical section andadjacent horizontal section of the core is achieved without adverselyaffecting the field concentration. Further, regions of the straps 302a-302 b located outside the grain oriented metal zone 308 may be removedfrom the transformer 300, thereby reducing overall weight. In at leastone embodiment, the first end of the center vertical strap 302 aincludes a non-grain orientation metal portion (not shown in FIG. 4B).

As described above, various embodiments may provide an electric deviceincluding a soft magnetically-conductive material having customizedgrain oriented portions. The electrical devices include, but are notlimited to, transformers, electrical machines, rotors inductors,sensors, actuators, Eddy current devices, etc. The grain orientedportions are strategically located with respect to the orientation offlux paths so as to reduce flux resistance, thereby improving theperformance and efficiency of the device. In terms of rotating machinessuch as PM motors, for example, an electric steel stator and/or rotormay be formed with grain oriented metal portions aligned radially alongthe radial direction of the stator teeth as well as circumferentiallyalong the outer circumference of the stator where the orientation of theflux paths are substantially constant and consistent. In transitionregions where the orientation of the flux paths vary and areinconsistent, non-grain oriented metal portions may be formed.

While the present disclosure has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the present disclosure is not limited to such disclosedembodiments. Rather, the present disclosure can be modified toincorporate any number of variations, alterations, substitutions orequivalent arrangements not heretofore described, but which arecommensurate with the spirit and scope of the present disclosure.Additionally, while various embodiments of the present disclosure havebeen described, it is to be understood that aspects of the presentdisclosure may include only some of the described embodiments.Accordingly, the present disclosure is not to be seen as limited by theforegoing description, but is only limited by the scope of the appendedclaims.

What is claimed is:
 1. An electrical device, comprising: anelectromagnetic component configured to generate a magnetic flux; theelectromagnetic component comprising a soft magnetically-conductivematerial configured to pass magnetic flux therethrough along a fluxpath, the soft magnetically-conductive material including at least onegrain oriented portion having metal grains that are oriented parallelwith respect to the magnetic flux, wherein the stator comprises atransition region interposed between a plurality of stator teeth and anouter yoke portion, wherein at least one of one or more stator teeth andthe exterior yoke portion has a grain oriented metal portion, andwherein the transition region has a non-grain oriented portion includingmetal grains having a substantially random orientation that does notmatch the magnetic flux paths of the transition region.
 2. Theelectrical device of claim 1, wherein the electromagnetic componentincludes a stator disposed adjacent a rotor that rotates with respect tothe stator.
 3. The electrical device of claim 2, wherein the statorcomprises the soft magnetically-conductive material.
 4. The electricaldevice of claim 3, wherein the soft magnetically-conductive material iselectrical steel comprising iron (Fe) and silicon (Si).
 5. Theelectrical device of claim 3, wherein the grain oriented metal portionhas a grain orientation that substantially matches a flux orientation ofthe flux path.
 6. The electrical devices of claim 5, wherein a firstgrain oriented metal portion of the stator teeth extending in directiontransverse to a respective stator tooth.
 7. The electrical device ofclaim 6, wherein a second grain oriented metal portion of the outer yokeportion has a circumferential orientation extending along acircumference of the outer yoke portion.
 8. The electrical device ofclaim 1, wherein the rotor includes at least one grain oriented metalrotor portion having rotor metal grains oriented substantially parallelto the metal grains of the first grain oriented metal portion.
 9. Theelectrical device of claim 1, wherein the electromagnetic componentincludes a plurality of vertical straps and a plurality of horizontalstraps that define an electrical transformer.
 10. The electrical deviceof claim 9, wherein each vertical strap includes a first vertical endcoupled to a first horizontal end of a respective horizontal strap todefine a corner zone, the corner zone including arched metal grainsextending in an arched manner from the vertical strap to the horizontalstrap.
 11. The electrical device of claim 10, wherein the plurality ofvertical straps includes a pair of opposing outer vertical straps and acenter vertical strap interposed between the outer vertical straps, andwherein the plurality of horizontal straps includes a first horizontalstrap having a first horizontal end connected to a first vertical end ofthe first outer vertical strap and a second horizontal end coupled to afirst end of the center vertical strap, and second a horizontal straphaving a first horizontal end connected to a first vertical end of thesecond outer vertical strap and a second horizontal end coupled to thefirst end of the center vertical strap.
 12. The electrical device ofclaim 11, wherein the first end of the center vertical strap includes anon-grain oriented metal portion.
 13. The electrical device of claim 10,wherein the vertical straps on the horizontal straps are formed ofelectrical steel comprising iron (Fe) and silicon (Si).
 14. Anelectrical device, comprising: an electromagnetic component configuredto generate a magnetic flux; the electromagnetic component comprising: asoft magnetically-conductive material configured to pass magnetic fluxtherethrough along a flux path, the soft magnetically-conductivematerial including at least one grain oriented portion having metalgrains that are oriented parallel with respect to the magnetic flux; anda plurality of vertical straps and a plurality of horizontal straps thatdefine an electrical transformer, each vertical strap includes a firstvertical end coupled to a first horizontal end of a respectivehorizontal strap to define a corner zone, the corner zone includingarched metal grains extending in an arched manner from the verticalstrap to the horizontal strap, wherein the plurality of vertical strapsincludes a pair of opposing outer vertical straps and a center verticalstrap interposed between the outer vertical straps, and wherein theplurality of horizontal straps includes a first horizontal strap havinga first horizontal end connected to a first vertical end of the firstouter vertical strap and a second horizontal end coupled to a first endof the center vertical strap, and second a horizontal strap having afirst horizontal end connected to a first vertical end of the secondouter vertical strap and a second horizontal end coupled to the firstend of the center vertical strap, and wherein the first end of thecenter vertical strap includes a non-grain oriented metal portion.